roots Flashcards
roots
greater than 50% of plant biomass, function in stability, communication, absorption, storage, and conduction of food, grow continuously
primary root
forms from the radicle, can be the taproot, base for branch roots to form off of
root cap
covers the apical meristem in the tip of each root for protection and gravity sensing
mucigel
layer of dead shedded root cap cells mixed with cytoplasm, lubricates the root, keeps it moist, contains chemicals to attract beneficial microbes
rhizosphere
soil and pieces of soil directly in contact with the roots
region of cell division
area directly above the apical meristem where embryonic tissues form
region of elongation
division stops and elongation begins, pushing the tip forward, cells start to mature
region of maturation
cells are fully grown and differentiated, root hairs form
cortex
ground tissue between the epidermis and vascular tissue, store starch in leucoplasts, made of parenchyma cells primary volume of the root
endodermis
inner most layer of cortex cells containing lignin and suberin, only found in roots, serves to screen out unwanted substances from entering the vascular tissue
casparian strip
layer if lignin and suberin on the cell walls of the endodermis in a ring
pericycle
outermost layer of the vascular tissue, location where branch roots begin to form, made of totipotent parenchyma cells
arenchyma
specialized parenchyma cells with large air spaces found in wetland plants in roots and stems
epidermis
1 cell thick protects the inner cells from the external environment, grow root hairs in the region of maturation
exodermis
old roots lose root hairs and gain a layer of suberin to seal out pathogens and act in storage
vascular cylinder
contains xylem and phloem and in monocots the pith
taproot
primary root remains, becomes long and anchors the plant
fibrous root system
primary root dies off leaving a wide bed of branch roots
adventitious roots
form off of the stem
air layering
method of propagation where a small cut is made in the original plant and kept open to form adventitious roots before the piece is cut off
pneumatophores
knees emerge from the ground to obtain oxygen, common in wetland plants
root nodules
house nitrogen fixing bacteria on the root for the plant to use, common in legumes, use leghemoglobin to regulate oxygen in the nodes
mycorrhizal fungi
can be inside or outside roots, fungi get carbs from the plant, plant gets increased water and nutrient absorption from the fungi
